* kdev_t: mask mi with MINORMASK in MKDEV macro
@ 2020-01-10 1:58 Zhiqiang Liu
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From: Zhiqiang Liu @ 2020-01-10 1:58 UTC (permalink / raw)
To: linux-kernel, dhowells, akpm, torvalds
Cc: bywxiaobai, Mingfangsen, Guiyao, zhangsaisai, renxudong
In MKDEV macro, if mi is larger than MINORMASK, the major will be
affected by mi. For example, set dev = MKDEV(2, (1U << MINORBITS)),
then MAJOR(dev) will be equal to 3, incorrectly.
Here, we mask mi with MINORMASK in MKDEV macro.
Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
---
include/linux/kdev_t.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/kdev_t.h b/include/linux/kdev_t.h
index 85b5151911cf..40a9423720b2 100644
--- a/include/linux/kdev_t.h
+++ b/include/linux/kdev_t.h
@@ -9,7 +9,7 @@
#define MAJOR(dev) ((unsigned int) ((dev) >> MINORBITS))
#define MINOR(dev) ((unsigned int) ((dev) & MINORMASK))
-#define MKDEV(ma,mi) (((ma) << MINORBITS) | (mi))
+#define MKDEV(ma, mi) (((ma) << MINORBITS) | ((mi) & MINORMASK))
#define print_dev_t(buffer, dev) \
sprintf((buffer), "%u:%u\n", MAJOR(dev), MINOR(dev))
--
2.19.1
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2020-01-10 1:58 kdev_t: mask mi with MINORMASK in MKDEV macro Zhiqiang Liu
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